Abstract
The behavior of heavy metals in cement paste is often investigated using a single species of heavy metal of which relatively soluble reagent is dosed in cement paste. In fact, however, several kinds of heavy metals could be incorporated in concrete where each heavy metal forms different kinds of compounds. In this study, incorporation of heavy metals in cement paste was simulated by addition of molten fly ash which is generated through the treatment processes of melting wastes. Using a sequential extraction test, heavy metals in cement paste were fractionated into the water-soluble fraction, neutral fraction, acid-soluble fraction and poorly-soluble fraction. As a result, although the water-soluble fractions of copper and zinc in molten fly ash account for about 40％ and 80％, respectively, most of them were altered to the acid-soluble fraction in cement paste, of which leaching risk will be relatively low. On the other hand, for lead in molten fly ash, soluble fractions increased by incorporating it in cement paste.
